TD Ameritrade sign (Photo: Shutterstock)

Desktop users of TD Ameritrade’s thinkorswim trading platform were unable to access it on Monday morning due to an outage caused by an unspecified “system issue.”

The outage, which followed multiple outages on the websites of TD Ameritrade and other financial firms earlier this year, led several investors to take to Twitter to complain about trades they were unable to make and money they lost as a result.

“Earlier this morning, we encountered a system issue that caused clients using the thinkorswim desktop application to experience difficulty accessing the platform,” a TD Ameritrade spokesperson told ThinkAdvisor at about 11:30 a.m. Eastern time.

However, “during this time, clients could access their accounts and place trades through all of our other platforms, including thinkorswim Web and the thinkorswim mobile application,” she said, adding: “We apologize for the inconvenience and take the performance and reliability of our trading platforms very seriously.”

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The spokesperson declined to specify when the outage started, how many people were impacted or specify what might have caused the outage.

At about noon on Monday, thinkorswim warned users on Twitter: “You may be temporarily unable to log on to thinkorswim on your desktop or laptop. We apologize and are working to fix this problem as soon as possible. In the meantime, please log in using thinkorswim Web or thinkorswim Mobile.”

Clients were still “able to access their accounts and trades are being processed as usual across all TD Ameritrade platforms,” the TD Ameritrade spokesperson said.

Thinkorswim tweeted an update at about 4:45 p.m. Eastern time, saying: “We appreciate your patience as we continue to work diligently to correct the issues today with TOS desktop. You are able to use TOS mobile, the website or TD Ameritrade app to place trades. We sincerely apologize for any inconvenience.”

Thinkorswim and TD’s thinkpipes trading platforms, educational resources and tools will be part of what Charles Schwab offers clients of independent advisors and other investors following Schwab’s acquisition of its former rival, set to wrap up by year-end, Schwab recently said.

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